im not sure whether to leave them or pull them
Have you planted any geums? If so, those are they
If you haven't, they might be the wild native version Geum urbanum = Wood avens. https://en.wikipedia.org/wiki/Geum_urbanum Not quite as pretty as their cultivated cousins.
If you're not sure I'd leave them and see what sort of flowers they have ... maybe next year now ... and then ask us which they are if you're still not sure.
Thank you Dovefromabove. We can't remember if we planted them as it would've been a long time ago. It is possible that they're wild as the area is very damp and woodland like. I don't think we've ever had flowers on them but i'll observe and come back next year!
When it flowers, if they are small and yellow, dig it up quick as it will be the weedy one, Geum urbanum which can become a real nuisance if it seeds. The seeds have burrs which stick to everything. I used to have a long haired cat and it would take hours to get all of the wood avens seeds out of its coat.
I have a little clump of them at the end of the garden, but they're outside the main garden under the pine tree, in a fairly inhospitable bit, and have never got into the main garden, so I can leave them to their own devices.
I see from your link that they apparently keep away rabid dogs and venomous snakes Dove - so it's not all bad!